Like many aspiring house-hunters, Gian Gonzaga and his wife saved gobs of money as they prepared to buy their first home. If you could have peeked into their bank accounts at the time, you might have spotted telling signs suggesting: “You look like you’re saving for a house,” Gonzaga recalls.

Gonzaga, chief data officer at the lending startup Earnest, has spent his career thinking about how people make choices, from earlier stints at the dating website eHarmony and the media company Netflix, to his current role looking at financial decision-making at Earnest. And he believes Earnest, which began as a refinancer of student loan debt, is in a unique position to know when its largely millennial customers are gearing up for a big financial choice by reading signals from their accounts, much as his own once indicated an intention to buy a home.

The potential of that massive millennial market is catnip for most companies eager to reach young customers and retain them as their resources grow. And Earnest could benefit from its unusual perspective of knowing when its borrowers are getting wealthier. Earnest, which had completed $1 billion in refinanced student loans through October since starting its program two years ago, can watch its borrowers’ assets change thanks to its business model which collects wide asset data and account information in attempt to better gauge borrower risk, then tracks those accounts over time. The company uses between 80,000 and 100,000 data points to underwrite the loans, including reviewing assets in lending decisions, as well as verifying income automatically, Gonzaga says.

So what are those accounts telling them? Not surprisingly, many of Earnest’s 20- and 30-something customers (the average age is late-20s-to-mid 30s with an average refinancing loan size of $70,000, according to the company) are starting new chapters in their lives. In an aim to reflect interest in new goals — and in a blatant marketing push — Earnest began publishing an online guide this month featuring research from the increasingly trendy field of behavioral economics.

Gonzaga, who holds a Ph.D. in psychology, says he has held a longtime fascination in one of the core tenets of the field: how people make tradeoffs between the short- and long-term — something that applies to both love and money. “My specific area was emotion,” he says.“How emotion affects choices.”

The new guide zeroes in on “big steps that are relevant for the generation that is in their 20s and 30s,” he says such as moving to a new city, buying a home or going to grad school. Articles delve in detail into cognitive biases like the tendency to focus overly on the present or the likelihood of becoming paralyzed when confronted by too much choice. The online guide will likely be followed by more targeted financial products in the future that will address their customer’s expanding financial needs, Gonzaga says.

“The truism is the more money you have the more financial products you need,” Gonzaga says.

Already, Earnest started underwriting personal loans and though Gonzaga declined to specify what other products the firm is eyeing he described an aim to establish itself over time as a “lifetime partner.”

It’s a smart move, especially given the company’s inroads with young people. Even if marketers regard millennials as a generation marked by different desires from prior ones, chances are their financial needs will resemble those of their elders. Despite the much-hyped gaps between millennials and everyone who has come before, there are only so many possible variations on mortgages, mutual funds and life insurance out there. At least for now.

Like you, I’m fascinated by the psychology of money and why people make the financial decisions that they do. For more than a decade, I’ve written about the topic—and many others in personal finance--for publications including The New York Times, SmartMoney, The Wall Street ...